Proteins Flashcards
what are the monomers of proteins?
amino acids
what do amino acids consist of?
- carboxyl group
- amine group
- side chain
how many different amino acids are there?
20 amino acids
how do the amino acids vary?
by having different side chains
why are some proteins essential?
need them in diet otherwise lead to protein malnutrition
what does it mean if proteins are non-essential?
the body makes them
which organ makes proteins?
liver
list 10 uses of proteins
- structure
- hormones
- pumps
- transport
- antibodies
- cell recognition
- receptors
- toxins
- blood clotting
- storage
how many amino acids form a dipeptide?
two amino acids
what type of reaction forms dipeptides/ polypeptides?
condensation reaction
what are two types of functional proteins?
- fibrous
- globular
what are the properties of fibrous proteins?
- made of long fibres
- coil into long helices (due to regular pattern of hydrogen bonds)
- strong - structural function - protection
- insoluble
what are properties of globular proteins?
-fold into balls/ globules
- soluble
-biochemical function: enzymes most common because shape has active site
(function depends on tertiary structure)
name three types of fibrous proteins
- collagen
- keratin
- chitin
name two types of globular proteins
- haemoglobin
- myoglobin
describe collagen
- it is a fibrous protein
- made of three polypeptide chains
- 30% glycine (simple amino acid with hydrogen as side chain)
- tightly wound and compact
describe haemoglobin
- it is a globular protein
- made of 4 polypeptide chains
- 4 haem groups Fe 2+ ions which carry oxygen
what is primary structure?
sequence of amino acids in a polypeptide chain
what is secondary structure?
- hydrogen bonds pull chains into regular pattern either alpha-helix or a beta-pleated sheet
what is tertiary structure?
3D shape that occurs due to the bonding between R groups
- hydrogen bonds
- ionic bonds
- disulphide bridges
what is quaternary structure?
tertiary structure for two or more polypeptide chains
